固相法制备LiMnPO_4/C及其电化学性能的研究  

Electrochemical properties of LiMnPO_4/C synthesized by solid state reaction method

作　　者：段婉璐[1,2] 李建刚[2] 赵鹏翔[2] 何向明[3] 刘才[2] 李巍[2] 翟彦青[2] 

机构地区：[1]北京化工大学理学院,北京100029 [2]北京石油化工学院应用化学系,北京102617 [3]清华大学核能与新能源技术研究院,北京100084

出　　处：《化工新型材料》2014年第11期110-112,共3页New Chemical Materials

基　　金：北京石油化工学院优秀责任教授和管理专家资助项目(BIPT-POPME-2013)

摘　　要：分别采用传统高温固相法、以表面活性剂辅助所制NH4MnPO4·H2O为前驱体的高温固相法合成了LiMnPO4/C材料,运用XRD、SEM、充放电测试、电化学交流阻抗频谱(EIS)等表征手段考察了不同制备方法对材料结构与性能的影响。结果表明,以表面活性剂辅助所制NH4MnPO4·H2O前驱体来合成LiMnPO4/C材料,可以显著减小初始晶粒尺寸至约30nm。表面活性剂种类对二次颗粒的形貌、结构和电性能有显著影响。以P123为辅助表活剂时,所制材料确保了小晶粒与低团聚的结构特性,有利于其与锂盐高温反应时得到相更纯、晶面生长更优、晶化度更高、与电解液接触面积更大、锂离子扩散更容易、电性能更优的LiMnPO4/C材料。该材料0.2C容量达116.6mAh/g,5C放电容量达79.8mAh/g,且在各倍率下均保持优良循环稳定性。LiMnPO4/C materials were prepared by solid state reaction method by using traditional raw materials, surfactant-assisted precipitated NH4 MnPO4 · H2O as reactants respectively,and the structural and electrochemical properties of as-prepared materials were characterized by using XRD,SEM, electrochemical impedance spectra（EIS）and charge-discharge tests. The results indicated that using surfactant-assisted precipitated NH4 MnPO4 · H2O as reactants can decrease remarkably crystalline particle size of LiMnPO4/C to -30nm. The type of surfactant presented great effects on the agglomerated particles morphology, struc ture and electrochemical properties. While P123 being used,as prepared precipitate with small crystal particle size and low agglomeration, can react with Li salt sufficiently to obtain LiMnPO4/C with more pure phase,well-oriented crystal growth and crystallization,more interface area with electrolyte, high Li diffusion rate, better electrochemical performance. It showed a capacity of 116. 6mAh/g at 0.2C,79.8mAh/g at 5C,and excellent cycling stability at different rates.

关 键 词：锂离子电池 正极材料 磷酸锰锂 固相法 

分 类 号：TM912[电气工程—电力电子与电力传动]